Biomedical subjects
Publications and source records attributed to G Bang.
Central mucoepidermoid tumour is an uncommon tumour within the jawbones. The onset is insidious and the first symptom is usually swelling. The radiographic appearance resembles a multiocular cyst or ameloblastoma. Two new cases are presented, and their diagnosis, histopathology and treatment are discussed. The prognosis is fairly good after adequate surgical treatment.
Arthroscopy of the rabbit temporomandibular joint was evaluated experimentally on 22 rabbits. A small arthroscope with so-called "Selfoc"-system was employed. The reaction to arthroscopy was analyzed clinically. Macroscopic dissection and histology were then employed to detect possible pathological changes in the joints at periodic intervals. The established criteria for evaluation of postoperative reactions were erythema, suppuration, weight changes and chewing capacity. The results of this study indicate that the rabbit temporomandibular joint may be arthroscoped with subsequent minor reversible changes. It also seems feasible to assume that temporomandibular joint arthroscopy in humans runs a low risk for postoperative complications.
A case of an ameloblastic carcinoma in an unusual situation in the maxilla is presented. The lesion is characterized histologically by areas with features of a typical ameloblastoma and areas with anaplastic transformation. A Caldwell-Luc operation was followed by a recurrence after 3 years. Due to the advanced age and poor general health of the patient an enlarged, but not radical operation was performed. There is no evidence of metastatic tumour.
Data on the permanent dentition of 63 coastal and 33 inland Alaskan Eskimos are presented. The number of cusps and groove pattern of the mandibular molars were recorded. Agenesis of the mandibular third molars was classified and the mesiodistal and buccolingual crown diameter was measured on the first and the second mandibular molars. The predominant pattern of the lower first molars was Y5, while for the second molar the dominating patterns were +5 and +4. In the lower third molar, +5 was found in the majority of cases. For M1 and M2, men showed a stronger tendency toward a conservative pattern than did women. In the case of M2, the inland population exhibited a more conservative trait than did the coastal population. No connection was seen between the groove pattern and agenesis of M3, however, a reduction in the mesiodistal crown diameter for the second molars was seen when the number of cusps is reduced from 5 to 4.
Verrucous carcinoma is a well-defined variant of the squamous cell carcinoma. Although it is reported to be rare in the Scandinavian countries, 16 cases have been diagnosed in the Southern part of Norway from 1975 to 1982. The clinical and histological characteristics were investigated. The most common site of occurrence was the mandibular alveolar ridge. The average age was 71 years, and unlike most other series of verrucous carcinoma, there was a female predominance and use of tobacco seemed to be the exception. The patients mainly complained of ill-fitting dentures. Adequate surgical excision appears to be the treatment of choice.
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Heterotopic salivary gland tissue in the upper neck is believed to be a rare entity, only 3 cases having been reported previously. We present 2 additional cases with a discussion of the possible origin of the tissue. Tumor formation was present in all cases.
Rigid intramedullary nailing of the right tibia after osteotomy with resection of the fibula was performed on 48 male Wistar rats weighting 300-400 g. Nailing was performed with 1.4-mm nails after reaming. Nail stiffness was similar to that of intact tibias. The left leg remained unoperated as control. The animals were sacrificed after 4, 8, 12 or 16 weeks, and both tibiae were tested in a 3-point bending test. Of the 35 animals with the nail in situ, nine animals showed non-union at the time of testing. At 8 weeks stiffness had reached normal values, while strength and deflection showed about half of normal values. Poor strength and small deflectability combined with near normal stiffness may be taken as evidence that Wolf's law is valid also in newly formed tissues of fracture healing; the protection given by a rigid nail makes normal strength and pliability unnecessary.
A 13-year-old girl was treated surgically for a giant-cell tumor of bone originating in the talus and for a recurrence in the distal tibia. She later developed liver and lung metastases and was treated for two years, five months with a combination of vincristine, doxorubicin, cyclophosphamide and actinomycin-D, and thereafter with high-dose methotrexate/vincristine with citrovorum factor rescue. A good response was obtained and the patient is without evidence of disease 12 months after a salvage thoracotomy for residual disease in the left lung. Aspects of this singular case are discussed.
Gradual distraction of a tibiofibular bone osteotomy in 14 rabbits was compared with a neutral osteotomy in 14 control rabbits using an osteotaxis device as fixation. The osteotomy was distracted for a period of 8 weeks at a rate of 1 mm/week. The control osteotomies united in 5 to 6 weeks with minimal external callus formation. In the distraction group, the periosteum and endosteum participated in the filling of the distraction gap. The most vigorous osteoblastic activity was observed in the middle of the osteotomy gap (growth zone) where calcification was delayed. In the distraction group the bone united in 6 to 7 weeks, not significantly later than in the controls. Two instances of non-union (2/14) were observed in the distraction group.
The efficiency of indomethacin (10 mg/kg/day) in inhibiting recurrent partial closure of the epiphyseal plate was tested in rabbits. An epiphysiodesis was done laterally in the distal left femoral epiphyseal plate in 10 adolescent rabbits. This produced a valgus deformity in 14 of them. The bone bridge was then removed operatively and the rabbits were treated with either indomethacin or vehicle for 21 days postoperatively. Indomethacin plasma levels were about 180 ng/ml. The valgus deformity improved in indomethacin-treated rabbits, whereas it became worse in the controls (P = 0.004).
Bilateral tibial osteotomy with fracturing of the fibula was performed on ten Wistar rats weighing 300--350 g. Intramedullary nailing was performed with 1.4 mm nails after reaming. On the left side solid stainless rods were used, while on the right side the nails had a middle part made of titanium-nickel wire covered with polyvinylchloride (PVC), giving the nail a high degree of flexibility. After 8 weeks, nine of the ten flexible nails showed fracture of the central wire. The continuity was, however, maintained by the PVC tube. The bones with flexible nailing always showed hypertrophic callus while there was only scanty callus on the side with rigid nailing. Strength, deformation at fracture and stiffness were measured in a three-point bending test after removal of the solid nails and the fibulae. The strength of the tibiae was greatest on the side with flexible nailing, as was the deformation at fracture. The mean stiffness was higher in the bones with rigid nails, but the difference here was not statistically discernible.
Allogenic demineralized dentin implanted in the abdominal wall of guinea pigs induced heterotopic osteoid and bone formation. Samples of this tissue were frozen at - 140 degrees C, freeze-dried at -80 degrees C, infiltrated with Spurr epoxy resin and polymerized. The sections were then studied in the scanning transmission electron microscope, and analytical studies were performed by means of energy dispersive microanalysis. Osteoblasts and young osteoid osteocytes contained more calcium than undifferentiated cells and mature osteocytes. The Ca/P ratio in the cytoplasm of these young matrix-producing cells was high. Phosphorus was found in the nuclei of all cells and to a lesser extent also in the cytoplasm of cells rich in calcium. The initial extra-cellular mineral accumulation also showed a high Ca/P ratio. Small electrondense areas in these regions exhibited an amount of calcium and a Ca/P ratio resembling those of mature mineralized bone. The initial event of the mineralization process seemed to be an accumulation of calcium first in the young matrix-producing cells and then in the surrounding osteoid matrix. The results suggested that the matrix-producing cells are actively involved in the accumulation of calcium and phosphorus both intra- and extra-cellularly.
The method of using split thickness skin grafts for vestibuloplasty operation has been carried out on 89 patients with atrophic mandibles. The patients have been followed-up at regular intervals over a 3-year period and show a stable operational result. The graft attaches to the periosteum of the alveolar ridge and maintains the new sulcus depth, preventing relapse. Measurements between tattoo marks on the transplant and on the transplant/mucosa junction show that this type of skin graft to the oral cavity is stable and results in only a slight initial amount of shrinkage, probably due to scar formation. Disadvantages of transplanting skin to the mouth such as hair growth or disagreeable odor did not occur. The patients accepted the color and the consistency of the graft. No complications following completed treatment have been found.
Three patients with psoriasis who developed nevus spilus-like hyperpigmentation during PUVA therapy are described. Histological studies of skin biopsies revealed no increase in the number of melanocytes or any sign of malignancy. The need for follow-up studies is stressed.
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An ameloblastic fibro-odontoma in a 14-year-old girl is reported. The case has clinical interest because of the location and the size of the tumor which was surgically enucleated. The different views about clinical, radiographical and histopathological characteristics and the classification of this benign tumor are discussed. The postoperative course was uneventful and the case has been controlled for 3 years without recurrence.